Jaroslav Kadlec, Radimír Vrba, Radek Helán
PRESSURE SENSING VIA OPTICAL INETRFEROMETRIC PRINCIPLE

This paper describes steps involved in a new type of pressure sensing. Significance of this approach and propose approaches for improving sensitivity, resistance to electromagnetic interference, dimensions and accuracy. The goal of the project is the research of complex smart pressure sensor based on the new sensing system with galvanic fiber optic isolation including research and experimental validation of this new pressure sensing principle.
The objectives of the project of applied research are in new methods and technology of pressure sensors with galvanic isolation and function specimen of smart optical pressure sensor for explosive industrial environment and/or environment with high electromagnetic interference and very high precision and absolute resistance to electric and magnetic interference.

Jorge C. Torres-Guzmán, Pablo Olvera-Arana, Luiz H. Paraguassú, Paulo R. G. Couto
COMPARISON BETWEEN INMETRO (BRAZIL) AND CENAM (MEXICO) ON BAROMETRIC PRESSURE, RANGE FROM 80 kPa UP TO 115 kPa

This paper presents the comparison between the Instituto Nacional de Metrologia, Normalização e Qualidade Industrial (INMETRO, Brazil) and the Centro Nacional de Metrología (CENAM, Mexico) on barometric pressure in the range from 80 kPa up to 115 kPa. This comparison was carried out at the end of 2004 and has been entered within the data base of the Sistema Interamericano de Metrología (Interamerican Metrology System, SIM) as comparison SIM.7.25 P. The pilot laboratory was CENAM. The standards used by the national laboratories were pressure balances, operated in free deformation. The transfer standard used for the comparison was a digital barometer, accuracy class of 0.01 % of full scale. Eight points of pressures were selected and each pressure was measured four times. The results obtained by the two laboratories were in agreement.

Alaaeldin A.E. Eltawil, Douglas Olson
CHARACTERIZATION OF A PRIMARY STANDARD CONTROLLED CLEARANCE PRESSURE BALANCE USING HEYDEMANN AND WELCH MODEL

For a traceable measurement to be verified and meaningful, it is important that all the measuring apparatus have to be calibrated against standards that are traceable to National/ International Standards. Calibration is a process that determines the operational integrity of mislaying instruments by determining their measurement uncertainties. In order to ensure the calibration of a measuring instrument traceable to National Standards, a hierarchy of standards and standards laboratories are established. A primary pressure standard that can metrologically characterized in a complete and an independent way with reference only to the basic units of the S.I. system, is defined as force per unit area (pressure balance) or the height of a liquid column (liquid manometer). Pressure balances are excellent primary standards for measuring pressure with high resolution and high accuracy. Characterization of primary standard pressure balance (controlled clearance) will be presented in this work.

Tokihiko Kobata
MEASUREMENT OF EFFECTIVE AREA RATIO OF GAS AND HYDRAULIC PRESSURE BALANCES

This paper describes a method to compare the pressure generated by gas and hydraulic pressure balances with different medium, in order to improve harmonization between a gas pressure standard and a liquid pressure standard. The pressure range compared is 0.5 MPa to 7 MPa. In the method, a gas-liquid exchanger is used and a precise pressure transducer is employed as a comparator to determine the equilibrium state between the two pressure balances. From the measurement result obtained from the method, it was shown that the effective area ratio of gas and hydraulic pressure balances was determined as a function of pressure with the estimated uncertainty in all the pressure ranges compared.

Gilder Nader, Paulo Tiago Fracasso, Paulo José Saiz Jabardo, José Pucci Caly, Wagner Cesar Bruna, Flavius Portella Ribas Martins, Eduardo Ferrara, Mikiya Muramatsu, Niklauss UrsusWetter, Marcos Tadeu Pereira
A LOW COST PARTICLE IMAGE VELOCIMETRY

A low cost PIV was developed for Fluid-flow measurement and studies of flow around structural models or industrial facilities in wind tunnels. The analysis were conducted in a 100 mm x 150 mm optical window. The results show that the PIV prototype is working even though further development is necessary.